<?php

/**
 * Debug is intended to replace the buggy PHP function var_dump and print_r.
 * It can correctly identify the recursively referenced objects in a complex
 * object structure. It also has a recursive depth control to avoid indefinite
 * recursive display of some peculiar variables.
 *
 * Debug can be used as follows,
 * <pre>
 * Debug::dump($var);
 * </pre>
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package system.utils
 * @since 1.0
 */
class Debug
{
        private static $_objects;
        private static $_output;
        private static $_depth;

        /**
         * Displays a variable.
         * This method achieves the similar functionality as var_dump and print_r
         * but is more robust when handling complex objects such as Yii controllers.
         * @param mixed $var variable to be dumped
         * @param integer $depth maximum depth that the dumper should go into the variable. Defaults to 10.
         * @param boolean $highlight whether the result should be syntax-highlighted
         */
        public static function d($var,$depth=10,$highlight=false)
        {
                echo self::dumpAsString($var,$depth,$highlight);
        }

        /**
         * Dumps a variable in terms of a string.
         * This method achieves the similar functionality as var_dump and print_r
         * but is more robust when handling complex objects such as Yii controllers.
         * @param mixed $var variable to be dumped
         * @param integer $depth maximum depth that the dumper should go into the variable. Defaults to 10.
         * @param boolean $highlight whether the result should be syntax-highlighted
         * @return string the string representation of the variable
         */
        public static function dumpAsString($var,$depth=10,$highlight=false)
        {
                self::$_output='';
                self::$_objects=array();
                self::$_depth=$depth;
                self::dumpInternal($var,0);
                if($highlight)
                {
                        $result=highlight_string("<?php\n".self::$_output,true);
                        self::$_output=preg_replace('/&lt;\\?php<br \\/>/','',$result,1);
                }
                return self::$_output;
        }

        /*
         * @param mixed $var variable to be dumped
         * @param integer $level depth level
         */
        private static function dumpInternal($var,$level)
        {
                switch(gettype($var))
                {
                        case 'boolean':
                                self::$_output.=$var?'true':'false';
                                break;
                        case 'integer':
                                self::$_output.="$var";
                                break;
                        case 'double':
                                self::$_output.="$var";
                                break;
                        case 'string':
                                self::$_output.="'".addslashes($var)."'";
                                break;
                        case 'resource':
                                self::$_output.='{resource}';
                                break;
                        case 'NULL':
                                self::$_output.="null";
                                break;
                        case 'unknown type':
                                self::$_output.='{unknown}';
                                break;
                        case 'array':
                                if(self::$_depth<=$level)
                                        self::$_output.='array(...)';
                                elseif(empty($var))
                                        self::$_output.='array()';
                                else
                                {
                                        $keys=array_keys($var);
                                        $spaces=str_repeat(' ',$level*4);
                                        self::$_output.="array\n".$spaces.'(';
                                        foreach($keys as $key)
                                        {
                                                self::$_output.="\n".$spaces.'    ';
                                                self::dumpInternal($key,0);
                                                self::$_output.=' => ';
                                                self::dumpInternal($var[$key],$level+1);
                                        }
                                        self::$_output.="\n".$spaces.')';
                                }
                                break;
                        case 'object':
                                if(($id=array_search($var,self::$_objects,true))!==false)
                                        self::$_output.=get_class($var).'#'.($id+1).'(...)';
                                elseif(self::$_depth<=$level)
                                        self::$_output.=get_class($var).'(...)';
                                else
                                {
                                        $id=array_push(self::$_objects,$var);
                                        $className=get_class($var);
                                        $members=(array)$var;
                                        $spaces=str_repeat(' ',$level*4);
                                        self::$_output.="$className#$id\n".$spaces.'(';
                                        foreach($members as $key=>$value)
                                        {
                                                $keyDisplay=strtr(trim($key),array("\0"=>':'));
                                                self::$_output.="\n".$spaces."    [$keyDisplay] => ";
                                                self::$_output.=self::dumpInternal($value,$level+1);
                                        }
                                        self::$_output.="\n".$spaces.')';
                                }
                                break;
                }
        }
}

